Hello Eric, Marc, > On 6 Jun 2023, at 09:33, Eric Auger <eauger@xxxxxxxxxx> wrote: > > Hi Marc, > > On 5/17/23 16:12, Marc Zyngier wrote: >> On Wed, 17 May 2023 09:59:45 +0100, >> Eric Auger <eauger@xxxxxxxxxx> wrote: >>> >>> Hi Marc, >>> Hi Marc, >>> On 5/16/23 22:28, Marc Zyngier wrote: >>>> On Tue, 16 May 2023 17:53:14 +0100, >>>> Eric Auger <eauger@xxxxxxxxxx> wrote: >>>>> >>>>> Hi Marc, >>>>> >>>>> On 5/15/23 19:30, Marc Zyngier wrote: >>>>>> This is the 4th drop of NV support on arm64 for this year. >>>>>> >>>>>> For the previous episodes, see [1]. >>>>>> >>>>>> What's changed: >>>>>> >>>>>> - New framework to track system register traps that are reinjected in >>>>>> guest EL2. It is expected to replace the discrete handling we have >>>>>> enjoyed so far, which didn't scale at all. This has already fixed a >>>>>> number of bugs that were hidden (a bunch of traps were never >>>>>> forwarded...). Still a work in progress, but this is going in the >>>>>> right direction. >>>>>> >>>>>> - Allow the L1 hypervisor to have a S2 that has an input larger than >>>>>> the L0 IPA space. This fixes a number of subtle issues, depending on >>>>>> how the initial guest was created. >>>>>> >>>>>> - Consequently, the patch series has gone longer again. Boo. But >>>>>> hopefully some of it is easier to review... >>>>>> >>>>>> [1] https://lore.kernel.org/r/20230405154008.3552854-1-maz@xxxxxxxxxx >>>>> >>>>> I have started testing this and when booting my fedora guest I get >>>>> >>>>> [ 151.796544] kvm [7617]: Unsupported guest sys_reg access at: >>>>> 23f425fd0 [80000209] >>>>> [ 151.796544] { Op0( 3), Op1( 3), CRn(14), CRm( 3), Op2( 1), func_write }, >>>>> >>>>> as soon as the host has kvm-arm.mode=nested >>>>> >>>>> This seems to be triggered very early by EDK2 >>>>> (ArmPkg/Drivers/TimerDxe/TimerDxe.c). >>>>> >>>>> If I am not wrong this CNTV_CTL_EL0. Do you have any idea? >>>> >>>> So here's my current analysis: >>>> >>>> I assume you are running EDK2 as the L1 guest in a nested >>>> configuration. I also assume that you are not running on an Apple >>>> CPU. If these assumptions are correct, then EDK2 runs at vEL2, and is >>>> in nVHE mode. >>>> >>>> Finally, I'm going to assume that your implementation has FEAT_ECV and >>>> FEAT_NV2, because I can't see how it could fail otherwise. >>> all the above is correct. >>>> >>>> In these precise conditions, KVM sets the CNTHCTL_EL2.EL1TVT bit so >>>> that we can trap the EL0 virtual timer and faithfully emulate it (it >>>> is otherwise written to memory, which isn't very helpful). >>> >>> indeed >>>> >>>> As it turns out, we don't handle these traps. I didn't spot it because >>>> my test machines are all Apple boxes that don't have a nVHE mode, so >>>> nothing on the nVHE path is getting *ANY* coverage. Hint: having >>>> access to such a machine would help (shipping address on request!). >>>> Otherwise, I'll eventually kill the nVHE support altogether. >>>> >>>> I have written the following patch, which compiles, but that I cannot >>>> test with my current setup. Could you please give it a go? >>> >>> with the patch below, my guest boots nicely. You did it great on the 1st >>> shot!!! So this fixes my issue. I will continue testing the v10. >> >> Thanks a lot for reporting the issue and testing my hacks. I'll >> eventually fold it into the rest of the series. >> >> By the way, what are you using as your VMM? I'd really like to >> reproduce your setup. > Sorry I missed your reply. I am using libvirt + qemu (feat Miguel's RFC) > and fedora L1 guest. > Following this subject, I’ve forward ported Alexandru’s KUT patches ( and I encourage others to do it also =) ) which expose an EL2 test that does three checks: - whether VHE is supported and enabled - disable VHE - re-enable VHE I’m running qemu with virtualization=on as well to run this test and it is passing although problems seem to happen when running with virtualization=off, which I’m still looking into it. Thanks Miguel > Thanks to your fix, this boots fine. But at the moment it does not > reboot and hangs in edk2 I think. Unfortunately this time I have no > trace on host :-( While looking at your series I will add some traces. > > Eric >> >> Cheers, >> >> M.
